Balanced Binary Tree

/**
 * Definition for binary tree
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    
    //求出树的最大深度
    public int deepth(TreeNode root) {
        if(root==null) return 0;
        else {
            int left = deepth(root.left);
            int right = deepth(root.right);
            return (left>right?left:right)+1;
        }
    }
    
    public boolean isBalanced(TreeNode root) {
        if(root==null) return true;
        if(Math.abs(deepth(root.left)-deepth(root.right))>1) return false;
        if(!isBalanced(root.left)) return false;
        if(!isBalanced(root.right)) return false;
        return true;
    }
}